The present invention relates to a substrate for amorphous silicon solar cells, more particularly to a substrate for forming thereon a plurality of solar cells as connected in series.
The percentages used herein and in the appended claims are by weight. The term amorphous silicon will be hereinafter abbreviated as "a-Si."
An assembly of solar cells connected in series is prepared, for example, by forming a plurality of lower electrodes of chromium or the like on a substrate by the electron beam vacuum evaporation process or the like, forming an a-Si layer on each of the lower electrodes, for example, by the chemical vapor deposition process (CVD process), covering the a-Si layer with a transparent electrically conductive film, and connecting the resulting cells in series. With such solar cell assembly, the lower electrodes must of course be electrically insulated from one another by giving an increased resistance value to the portion between the lower electrodes.
Accordingly the substrates heretofore used for solar cell assemblies of the type described include a stainless steel plate having a polyimide resin surface coating serving as an electric insulation layer, and a glass substrate. However, the former has the problem of encountering difficulty in reducing the cost of solar cells because the stainless steel plate and polyimide resin are very expensive, while the latter has the problem of being low in heat dissipating property and fragile.